AR-2019-2020

SuGOHI-IV. Lensed quasar search in the HSC survey Strong gravitationally lensed quasars provide a powerful means to study galaxy evolution and cosmology. Anupreeta More and collaborators use CHITAH, an algorithm to hunt for new lens systems, particularly lensed quasars, in the Hyper Suprime-Cam Subaru Strategic Program (HSC SSP) S16A. A sample of 46 lens candidates are presented, of which 3 are previously known. The six most promising candidates were confirmed with spectroscopy. The authors apply the software GLEE to model the six confirmed lenses uniformly. Through the analysis of the HSC images, it is noted that three systems appear to have point-like sources, which may or may not AGNs intrinsically. Using emission line widths and diagnostics, one of the sources was found to be a probable quasar and another source was found to be a Lyman- α emitter. STRIDES: A 3.9 per cent measurement of the Hubble constant from the strong lens system DES J0408-5354 A blind time-delay cosmographic analysis for the lens system DES J0408-5354 is presented. This system is extraordinary for the presence of two sets of multiple images at different redshifts, which provide the opportunity to obtain more information at the cost of increased modelling complex- ity with respect to previously analyzed systems. Anupreeta More and collaborators combine the measured time delays, line-of-sight central velocity dispersion of the deflector, and statistically constrained external convergence with lens models to estimate two cosmological distances. The ”effective” time-delay distance corresponding to the redshifts of the deflector and the lensed quasar and the angular diameter distance to the deflector, with covariance between the two distances, are measured. From these constraints on the cosmological distances, the Hubble constant is inferred to be H 0 = 74 . 2 − 3 . 0 + 2 . 7 kms − 1 Mpc − 1 assuming a flat LCDM cosmology. This measurement gives the most precise constraint on H 0 to date from a single lens, which is consistent with mea- surements of H 0 based on the local distance ladder, reinforcing the tension with the inference from early universe probes, for example, with 2.2 σ discrepancy from the cosmic microwave background measurement. X-ray study of the double source plane gravitational lens system Eye of Horus observed with XMM-Newton A double source plane (DSP) system is a precious probe for the density profile of distant galaxies and cosmological parameters. However, these measurements could be affected by the surrounding environment of the lens galaxy. Thus, it is important to evaluate the cluster-scale mass for detailed mass modelling. The Eye of Horus, a DSP system discovered by the Hyper Suprime-Cam Subaru Strategic Survey (HSC-SSP), was followed up with XMM-Newton. Anupreeta More , Surhud More and collaborators detected two X-ray extended emissions, originating from two clusters, one centred at the Eye of Horus, and the other located ∼ 100 arcsec north-east to the Eye of Horus. The dynamical mass assuming hydrostatic equilibrium was determined, and their contributions to the lens mass interior of the Einstein radius was evaluated. The contribution of the former cluster is 1 . 1 +1 . 2 − 0 . 5 × 10 12 M , which is 21-76 per cent of the total mass within the Einstein radius. The discrepancy is likely due to the complex gravitational structure along the line of sight. On the other hand, the contribution of the latter cluster is only ∼ 2 per cent on the Eye of Horus. Therefore, the influence associated with this cluster can be ignored. Discovery of an unusually compact lensed Lyman break galaxy from Hy- per Suprime-Cam survey HSC J0904-0102, a quadruply lensed Lyman-break galaxy (LBG) in the survey of gravitationally- lensed objects in Hyper Suprime-Cam Imaging (SuGOHI) has been reported by Anupreeta More and collaborators. Owing to its point-like appearance, the source was thought to be a lensed active